A power transmitting coupling includes a hub member such as a yoke and a shaft such as a splined shaft fitted therein axially slidably but nonrotatably relative to each other, and detent balls accommodated in the hub member and partially extending into a ball setting groove of the shaft for preventing...http://www.google.com/patents/US4645372?utm_source=gb-gplus-sharePatent US4645372 - Power transmitting coupling
